The present invention relates to an electronic-mail system for transmitting/receiving an image in an electronic-mail format through a computer network such as the Internet.
A conventional facsimile apparatus transfers image data through a telephone line in accordance with a facsimile procedure defined by the international standards.
In a fee system employed by telephone lines in a public telephone network or the like, the communication enable time per unit charge becomes short depending on the distance. For this reason, the communication charge is imposed heavily as the distance increases.
To reduce the communication fee, a facsimile apparatus for converting image data into the electronic-mail format and transmitting it as electronic mail through the Internet is known, as disclosed in, e.g., U.S. Pat. No. 5,881,233.
In the Internet, clients are not charged for data transfer between providers (Internet connection traders). More specifically, a client is charged for only data transfer between the client and provider independently of the distance to the final data transmission destination. Hence, as the communication distance increases, the cost merit becomes large.
FIG. 10 shows the arrangement of the facsimile apparatus of this prior art.
As shown in FIG. 10, this facsimile apparatus comprises a CPU 1, a ROM 2, a RAM 3, an external storage section 4, a format conversion section 5, a format inversion section 6, a scanner section 7, a panel section 8, a compression/decompression section 9, a LAN control section 10, and a printer section 11.
In this facsimile apparatus, a facsimile document is set on the scanner section 7. In this state, when the electronic-mail address of a transmission destination is input from the panel section 8, and a start button is depressed, the transmission procedure starts. In the transmission procedure, the facsimile document is read by the scanner section 7 to generate image data. The image data is compressed by the compression/decompression section 9. Resultant binary compressed data is temporarily stored in the external storage section 4 such as a hard disk drive.
The format conversion section 5 converts the binary compressed data into character code data comprised of a combination of 7-bit character codes and also adds, to the character code data, a header describing the transmission destination electronic-mail address, transmission source electronic-mail address, data format, and character code conversion scheme, thereby converting the character code data into electronic-mail data having an electronic-mail format. As the electronic-mail format, a format based on, e.g., the MIME (Multipurpose Internet Mail Extensions) as the electronic-mail standard is used.
The LAN control section 10 sends the electronic-mail data obtained by the format conversion section 5 to a computer network such as the Internet using an electronic-mail transfer protocol such as the SMTP (Simple Mail Transfer Protocol).
An electronic-mail server (not shown) for managing electronic mail is connected to the computer network. Upon receiving the electronic-mail data sent in the above way, the electronic-mail server transfers the mail to the transmission destination address described in the header.
The facsimile apparatus periodically issues, to the electronic-mail server, a transfer request for electronic-mail data addressed to the self apparatus using the POP (Post Office Protocol). When electronic-mail data addressed to the self apparatus is present, the electronic-mail data is transferred from the electronic-mail server. The facsimile apparatus receives the electronic-mail data and temporarily stores it in the external storage section 4.
The format inversion section 6 converts the character code data into binary compressed data. The data is expanded by the compression/decompression section 9 to reproduce image data. This image data is temporarily stored in the external storage section 4.
The image data stored in the external storage section 4 is supplied to the printer section 11 to print an image corresponding to the image data.
The conventional facsimile apparatus for transmitting/receiving an image through the computer network uses a scheme of one-sidedly transmitting an image file attached to electronic mail, in which various conditions such as the resolution, image size, and compression scheme are described in advance as permanent conditions, from the transmission side to the reception side. This image transmission mode will be referred to an S mode (first transmission mode).
On the other hand, a general facsimile apparatus for transmitting image data through a telephone line negotiates first to recognize the capability (usable resolution, image size, compression scheme, and the like) of the other party and transmits image data under conditions corresponding to the capability of the other party. In addition, the facsimile apparatus confirms, on the basis of a confirmation signal returned from the other party, whether the image data is normally received.
Use of this scheme, i.e., negotiation and transmission confirmation, even in facsimile apparatuses using electronic mail has also been examined. This image transmission mode will be referred to a B mode (second transmission mode) hereinafter.
In the B mode, first, the image transmission source transmits capability request mail for requesting notification of the capability to the image transmission destination. Upon receiving the capability request mail, the image transmission destination returns capability answer mail attached with capability information (DIS) (Digital Identification Signal) representing the self capability to the image transmission source. The image transmission source appropriately sets conditions for image data to be transmitted on the basis of the capability information attached to the capability answer mail, converts the image in accordance with the conditions, and transmits compressed image data attached to electronic mail. At the image transmission destination, the image is expanded and printed. When processing is ended, confirmation mail representing the end of processing is returned to the image transmission source. Hence, in the B mode, four electronic-mail messages are transferred in one communication cycle.
For an apparatus compatible with both the S and B modes, when the mode of the apparatus at the image transmission destination is unknown, capability request mail is sent from the transmission side to the reception side. If capability answer mail is returned, it is determined that the image transmission destination is in the B mode. If no answer is returned in a predetermined time period, it is determined that the image transmission destination is in the S mode.
When the image transmission destination has an apparatus compatible with the S mode, the time is wasted to wait for the capability answer mail after necessity of image transmission arises and until actual image transmission is started. Hence, instantaneity of communication is lost.
When the image transmission destination has an apparatus compatible with the B mode, the efficiency lowers because mail for capability exchange is transmitted every time.
As described above, conventionally, the mode at the image transmission destination is determined on the basis of the presence/absence of arrival of capability answer mail for capability request mail. For this reason, image transmission cannot be efficiently performed.
It is an object of the present invention to provide an electronic-mail system capable of more quickly starting actual image transmission and efficiently performing image transmission.
According to the present invention, there is provided an electronic-mail system comprising address storage means for storing an electronic-mail address, mode information representing whether the other party apparatus having the electronic-mail address is compatible with the first transmission mode or the second transmission mode, and, when the other party apparatus having the electronic-mail address is compatible with the second transmission mode, capability information representing a capability of the other party terminal, the electronic-mail address, mode information, and capability information being in correspondence with each other; address registration means for registering the electronic-mail address, the mode information, and the capability information in the address storage means; determination means for determining whether an electronic-mail address designated as a transmission destination is stored in the address storage means; decision means for, when the determination means determines that the electronic-mail address designated as a transmission destination is stored in the address storage means, deciding the transmission mode to be used, on the basis of the transmission mode information stored in the address storage means in correspondence with the designated electronic-mail address, and when the transmission mode is decided to the second transmission mode, deciding communication conditions of the image to be transmitted, on the basis of the capability information stored in the address storage means in correspondence with the designated electronic-mail address; and electronic-mail transmission means for transmitting the image, for which the communication conditions are decided by the decision means, in an electronic-mail format through a computer network.
According to the present invention, actual image transmission can be quickly started, and an image can be efficiently transmitted.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.